* lisp/progmodes/prolog.el: Fix various indentation cases

(prolog-operator-chars): New const (add \\).
(prolog-smie-forward-token, prolog-smie-backward-token): Use it.
(prolog-smie-rules): Add rules according to bug#21526.

1 files changed, 39 insertions, 13 deletions

diff --git a/test/indent/prolog.prolog b/test/indent/prolog.prolog
index 6bf9437b883..9ac6df1b6c7 100644
--- a/test/indent/prolog.prolog
+++ b/test/indent/prolog.prolog
@@ -1,16 +1,18 @@
 %% -*- mode: prolog; coding: utf-8; fill-column: 78 -*-
 
 %% bug#21526
-test1 :-
+test21526_1 :-
     (   a ->
-            (   a ->
-                b
-            ;   c
-            )
-    ;   c
+        (   a ->
+            b
+        ;   c
+        )
+    ;   % Toto
+        c ->
+        d
     ).
 
-test2 :-
+test21526_2 :-
     (    a
     ->   (   a,
              b
@@ -19,7 +21,31 @@ test2 :-
          b2
     ;    c1,
          c2
-    )
+    ).
+
+test21526_3 :-
+    X \= Y,
+    \+ a,
+    b,
+    \+ \+ c,
+    d.
+
+test21526_4 :-
+    (   \+ a ->
+        b
+    ;   \+ c,
+        \+ d
+    ).
+
+
+test21526_5 :-
+    (a;
+     b ->
+         c).
+
+test21526_predicate(c) :- !,
+    test_goal1,
+    test_goal2.
 
 %% Testing correct tokenizing.
 foo(X) :- 0'= = X.
@@ -74,11 +100,11 @@ subst(X, V, FV, lambda(Y, Ti, Bi), lambda(Y1, To, Bo)) :-
     %% If X is equal to Y, X is shadowed, so no subst can take place.
     ->  Y1 = Y, Bo = Bi
     ;   (member((Y, _), FV)
-         %% If Y appears in FV, it can appear in V, so we need to
-         %% rename it to avoid name capture.
-         -> new_atom(Y, Y1),
-            subst(Y, Y1, [], Bi, Bi1)
-         ; Y1 = Y, Bi1 = Bi),
+        %% If Y appears in FV, it can appear in V, so we need to
+        %% rename it to avoid name capture.
+        -> new_atom(Y, Y1),
+           subst(Y, Y1, [], Bi, Bi1)
+        ; Y1 = Y, Bi1 = Bi),
         %% Perform substitution on the body.
         subst(X, V, FV, Bi1, Bo)
     ).